How does ethernet work on twisted pair?

Question

Computer networks

How does ethernet work on twisted pair? Why does a forced switch to 10Mbps bring the link up when the link doesn't go up to 100Mbps with auto-negotiation? (even on a small cable section of 10-20 meters) Is it possible to get ethernet on just one pair of wires?

Answer 1

the task of auto-negotiation is not primarily to determine the quality of the channel, but to coordinate the modes of operation supported by devices .
if the channel is rubbish, then manually clamping the speed can create the appearance of solving the problem
on one pair of wires, you can start ethernet. only, if you follow the standard, one of the wires must be cylindrical, and the second pass inside it. the assembly is called "coaxial cable". Depending on the thickness of the cable, this will be either Ethernet 10BASE-2 or 10BASE-5

Answer 2

Something like this, at the bottom of the link to the details and RFC
https://en.wikipedia.org/wiki/Autonegotiation

Answer 3

Well, here's one of the solutions for
you pag3.narod.ru/fullduplex/FullDuplex.htm
and specifically the diagram of the balancing part.